US2263649A - Post type yieldable barrier - Google Patents

Description

Nov. 25,1941. E. D. SAWYER POST TYPE YIELDABLE BARRIER Filed April 4 1938 3 Shee s-Sheet l r f M SM f w 2 H y m L N\h M N 7 PM v .m N \Zn IR- K N\ a NM N R\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\Rm\ r w y ,m w

Nov. 25, 1941. E. D. SAWYER POST TYPE YIELDABLE BARRIER Fil ed April 4, 1938 3 Sheets-Sheet 2 witnesses I Nov. 25, 1941. E. D. SAWYER PQST TYPE YIELDABLE BARRIER Filed April 4, 1938 3 Sheets-Sheet 3 u- Zvmswfor il l llll IWHH MIME '5 z 1w W '&

Patented Nov. 25, 1941 UNITED STATES PATENT OFFICE) POST TYPE YIELDABLE BARRIER Emerson D. Sawyer, Chicago, Ill.

Application April 4, 1938, Serial No. 199,933

3 Claims.

My invention relates to certain novel improvements in yieldable barriers, and has for its principal object the provision of an improved construction of this character, which can be used efliciently on small intermittently operated movable bridges, street ends. ferries, and roadway approaches to dock fronts, as well as being used for yieldable guard rails on roadway curves or points of danger on roadways at high embankments.

The present invention relates especially to that type of yieldable andv flexible barrier, in which the yielding net or obstruction member is either swung across the roadway, pulled across manually, or strung along the side of the roadway and kept in a taut horizontal position by means of intermediate supporting posts fitted with stapled loops through which the flexible barrier strands can render.

Another object of this invention is the provision of an efficient means of stopping cars, buses and trucks at places of danger without having to install more expensive types of yieldable barriers which utilize motive power for bringing the barrier net, or flexible retardation member, into an operative position across or alongside the roadway. Yieldable barriers using motive power for bringing the barrier net from above the roadway to an operative position across the roadway, have been constructed on a fairly large number of bridges in the past few years, and have afforded efficient protection on these bridgesybut the present invention will afford a means for resistively stopping traiiic from running wild on smaller and less frequently operated bridges, as

well as preventing traflic from hurdling or smashing through the guard rail at the side of the road.

Other objects will appear hereinafter.

The invention consists inthe combination and arrangement of parts hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings forming a part of this specification, and in which,

Figure 1 is a general View of the yieldable barrier device showing the posts with the net stretched therebetween.

Fig. 2 is a general View showing the posts of the barrier device with the flexible net mounted on and supported by semi-rigid breakable swinging members and having the net secured together near the center of the roadway with a pair hand tightening hooks.

Fig. 3 is a view taken on they line AA of 2 showing how the semi-rigid frame supporting the net can be swung through an angle of degrees when the hand tightening hooks are disconnected.

Fig. 4 is a section taken on the line BB of Fig. 2 showing the cables of thenet clamped to and supported by the semi-rigid frames.

Fig. 5 is asection taken on the line 0-0 of Fig. 2 showing the spreader strips. as connected to the horizontal cables of the net.

Fig. 6 is an enlarged detail of atypical top hinge for the swinging semi-rigid gate shown in Fig. 2.

Fig. '7 is a plan view showing the edge of the roadway slab at a curve in the roadway with thefiexible yieldable barrier strung along the shoulder of the curve of the roadway with assumed successive positions of an automobile at the time it leaves the roadway slab and crashes through the guard rail cables, and then is stopped by the cables in an extended position.

Fig. 8 is an enlarged elevational view taken on about the line D-D of Fig. 7 showing the extensible end of the yieldable barrier road guard.

Fig. 9 is a typical side view of one of the intermediate supporting-posts of the road guard shown in Fig. 7 and illustrates the renderable method of supporting the horizontal strand of the road guard.

Fig. 19. is a face view of the yieldable barrier post which contains the payout members and the braking devices.

Fig. 11 is a side view of the same post shown in Fig. 10. i

Fig. 12 is a partial top view of the post shown in Fig. 11 and is taken on. the line E-E with the ca removed, but in this Fig. 12 only those parts are shown that are sufficient to illustrate and describe the mechanism that cannot be brought out fully in Figs. 10 and 11.

Fig. 13 is a view taken from the back of the post on about the line FF of Fig. 11 showing the pivotal method of mounting the hand crank retrieving mechanism.

Fig. 14 is a view taken on about the line G-G of Fig. 11 showing the brake tightening lever locking device not shown on Fig. 11 for the purpose of clarity.

Fig. 15 is a view showing the top of the lock shown in Fig. 14 and taken on the line H-H.

The. general objective in the construction of roadway gates or guard rails is primarily to provide safety, and in order to be a safe resistive device constructions of this nature must yield in order to avoid stopping the vehicle so abruptly as to telescope the car and severely injure the occupants. Safety devices depending primarily upon the yielding qualities of either tension or compression springs invariably have a detrimental recoil or kick-back, and when this latter type of device is struck a really substantial blow, these springs are generally stressed beyond their elastic limit causing a permanent deformation of the spring and a detrimental sag of the flexible roadway net or longitudinal suspension members in the safety device.

To stop a moving vehicle gradually by means of a flexible safety device requires the application of negative resistance equal to the impact force of the moving vehicle. The impact force of moving vehicles as well as the opposing force required to stop those vehicles is computable in foot pounds of work done, hence it is readily seen that if the distance in which a vehicle is checked is measured in feet instead of inches, the restraining pull of the flexible part of the safety device will be proportionally smaller. The practical elongation or compression of spring devices is generally limited to only a few inches, whereas frictional retardation can be applied efficiently over distances of many feet.

By the application of this principle of snubbing action or frictional retardation to yieldable roadway barriers or guard rails, more efficient operation and less breakage can be obtained, thus affording greatersafety and more continued effectiveness. These are objects of the present invention.

Referring particularly to Fig. 1, the numeral 1 indicates the posts containing the braking or snubbing device and the numeral 2 indicates the longitudinal members of the net stretched between these posts I. I prefer to show the net members 2 laced together with flexible vertical members 3 and flexible diagonal members 4. The engaging hooks 5, secured to the horizontal members 2 by means of the take-up members 6, engage loops 1 formed in payout members or sockets 8, which are in turn set in openings in the faces of the posts I. Also in the type of construction as shown in Fig. 1, I prefer to show the horizontal members 2 being joined near the center of the roadway by means of two interlocking loops 9. The object of this construction is primarily for the purpose of folding the whole net back upon itself when it is desired to disconnect it by unhooking the hooks and placing the net alongside of the left hand post l clear of the roadway.

With the above general disposition of the parts named an effective yieldable barrier mechanism is obtained. In order to remove the barrier obstruction from the roadway it is necessary only to release the take-up members 6, disengage the hooks Sand pull the net to one side of the roadway, and in order to effectively barricade the roadway it is only necessary to pull the net across the road, engage the hooks 5 in the loops 1, and tighten up the strands of the net by means of the take-up members 6. Of course the use of loops l0 engaging the socket loops I at one end of the net is an optional construction in place of using hooks on both ends of the net. In Fig. 2 an alternate means of placing the flexible net athwart the roadway is shown, and

wardly from the posts I consist of the same horizontal members 2, verticals 3a and diagonals 4, and the longitudinal members 2 are secured swingably in the loops 1 formed in the pay-out members 8. With the construction as shown in Fig. 2 it is advantageous to maintain the longitudinal net members 2 in a slightly arched curve equivalent to the same radius of curvature as the crown of the roadway, so as to make it possible for a car to engage the net at the same height whether the vehicle strikes near the center of the road or at the side of the road. Also with this construction as shown in Fig. 2 I prefer to show the members 3a of the net as being formed of a bendable though semi-rigid metallic strip, as with this construction the net does not have to be rolled or pulled across the roadway and is at all times supported by the swinging gate members. Thisis best shown in Fig. 5.

The swinging gate members which support the net in its arched position consist of horizontal members ll, vertical members l2, and diagonal members l3. These members ll, [2 and I3 are bolted together so as to form a structurally selfsustaining frame as shown in Fig. 4 and are joined pivotally to the posts I by means of a hinge arrangement consisting of end pieces [4, tongues l5 and I511, pins l6 and hinge sockets H. These hinge sockets I! are secured to the posts I so as to have the pin I6 fall directly above the openings in loops 1, the object of this being to have the flexible net and the semi-rigid framework swing on the same center.

The normal operation of a flexible yieldable barrier gate such as shown in Fig. 2 would be as follows: swing the gate frames from their open position alongside of the curbs, as indicated is possible in Fig. 3, to a position directly across the roadway between the posts I, engage the hooks 5 in the loops l8, and then tighten these engaging hooks 5 in their loops l8 by means of take-up 6.

Should this whole gate arrangement as shown in Fig. 2 be struck by a car traveling only at a low speed, the strength of the cable net and the retardation pull on the sockets 8 from within the posts l would be suflicient to overcome the impact of the car with the flexible net being extended only a short distance, presumably less than 12 or 18 inches. In this case the horizontal strands and the diagonal strands of the net could render through the loops 20, as best shown in Fig. 4, without any material damage to the framework of the semi-rigid gate support consisting of members H, l2 and I3. But should a car strike this gate with its attached net at a relatively high speed, then my construction affords a means of permitting the rigid sustaining gate structure to follow along with the flexible net. As shown in Fig. 3 the gate when inoperative is swung in the direction indicated by y, and when the vehicle strikes the net the supporting frame tends to turn in the direction indicated by the arrow 3: of Fig. 3. Yet after the fairly high speed vehicle has deflected the net in an appreciable distance as indicated at a: of Fig. 3, then the hinge connections consisting of members l4, l5, I5a, l6 and I! are so constructed that the semi-rigid frame can separate and allow the whole structure of the semi-rigid gate to follow along with the flexible net as it is pushed into a fairly well extended position. The payout members which restrain the pull on sockets 8 will be described hereinafter. In the hinge construction, best shown in Fig. 6, I provide a shear-off key l9. This is provided for the two top hinges only and is of sufiicient strength only to resist the static load of the gate frame and net in its normal position, but will readily shear off at a very small percentage of the pullt'that can be exerted on the payout members which resist the pulling out of sockets 8. It is not necessary of course to provide the tongues I of the lower hinges with similar shear-off pins.

After the car has been stopped the roadway can again be opened to traffic by swinging the framework and the net to the sides of the roadway, thereby allowing trafiic to proceed. And thereafter the tongues I5 can be socketed in the frames I4 and new pins I9 installed in the upper hinges. This is nothing but a manual simplified repair operation. The recoiling of the payout members attached to the sockets 8 will be described hereinafter.

Now referring to Fig. 7, the curved line 20 which terminates in two tangential extremities indicates the edge of a roadway slab on which car 2I ismoving. For illustration: it is assumed that the car 2|. after having reached the position 2Ia with its right hand front wheel off the edge of the roadway slab becomes unmanageable and strikes one of the guard rail intermediate posts, such as in position 2Ib, and then after shearing off that post and possibly an adjacent post extends the horizontal members 22 of the guard rail to position 22a, but in so doing it is brought to a stop as indicated at 2Ic.

This extensible provision is best illustrated in Fig. 8, in which numeral I indicates a yieldable barrier post similar to that described above and as shown in Figs. 1 and 2. Numeral 23 indicates an extra heavy corner post on which cable slide sockets'24 are secured. These slide sockets 24 permit the cables 22 to slip through them fairly readily. Similar staple sockets 25 are fitted on the intermediate posts 26 of the guard rail, as best shown in Fig. 9, and these sockets 25 also permit the horizontal tension members 22 to slide there-through. At the end of the guard rail I prefer to show an extra heavy post 21, in which the two horizontal members 22 are secured, although it is entirely possible to have an extra heavy post, suchas 23, as well as another post I with snubbing mechanism in place of the fixed post 21. At intervals along the horizontal members 22 I show vertical spacing members 28 of the same type as members 3a of Fig. 2 and mounted on the horizontal members 22 so that theycan be rendered along the horizontal strands 22, yet normally serving as a semi-flexible tie so as to keep the members 22 at an equal distance from each other;

Again referring to Fig. 8, I provide a rigid and sturdy metallic spacer 29 attached at the ends of the horizontal members 22 and so secured that in case the members 22 are pulled horizontally due to a deflection such as at 22w the member 29 will engage the sockets 24 on the large post 23 in order to limit the slippage of the horizontal members 22 and to restrain them from being extended any further. Of course when such movement of the rigid spacer 29 occurs horizontal members 31!, which are secured substantially to horizontal members 22 by fastenings 3|, must also be pulled horizontally, and this in turn pulls the payout sockets 8 out of the main post I against a payout resistance as hereinafter described. Diagonal members 32 are provided in order that should the main portion of the load due to the impact of the car 2| fall on either the upper or lower strand of horizontal members 22, then both thesockets 8 of post I will be pulled out from the post I practically uniformly, as, described hereinafter in the specification.

I have preferred to show the post I when used in connection with a guardrail construction to be located well off the slab of the roadway, such as is brought out in Fig. '7. The object of this semi-remote location, together with a concrete protection as indicated by numeral 33 is for the purpose of not endangering this post I on account of direct impact from a car, and further to enable a single man to effectively replace the guard rail in its substantially correct position after the car 2I of Fig. '7 has been pulled back onto the: roadway. My improved construction permits of such simple replaceal. This is accomplished' by winding the payout cables attached to sockets 8 back into the post I, and the cables 22, which are the longitudinal tension members of the guard rail, are pulled back. along the faces of the posts 26 and the post 23 through the sockets 25. and 24. Due to the method of fastening members 28 onto horizontals 22, these members 28 in case they are displaced can be slid along the cables 22 for realignment.

In this illustrated construction calling for a novel, flexible, yieldable, resistive guard rail, I prefer to place the vertical member or spacer 29 at such a distance from the main corner post 23 so that the member 29 will contact the sockets 24 before the full payout length of the cables wound on the brake drums within post I and attached to sockets 8 shall have been fully unwound from their respective drums, as will be described hereinafter. This novel arrangement will permit of the braking apparatus within the post I functioning to its full efliciency and then permit the full pull in addition to this payout resistance to fall on the large post 23.

Now' referring more particularly to Figs. 10, ll, 12, 13, 14 and 15, which show the mechanism preferably contained in the main barrier posts, consisting chiefly of the payout members, the storage drums, the braking mechanism, and the retrieving mechanism. The numeral 34 indicates a machinery housing which forms a virtual inner shell for the post I and is so constructed as to be made removable from the post I for the object of maintenance renewals, although at the same time the various pieces of machinery could just'as well be mounted directly in the shell of the post I. The tie plates 35 and 36 are shown removable so as to allow the inner housing 34 to be taken directly out of the top of the post I after the cap 31 has been removed. The sockets 8 are provided with tapered bases which are seated in correspondingly tapered openings in the fair leader chocks 38. The payout cables 39 and 33a being secured in the sockets 8 pass tautly back into the post I, or within the housing 34, onto the storage drums 4B and 4| and whereby all slack is eliminated from the payout cables and the barrier sockets fl definitely positioned and supported. These payout members 39 and 39a in being coiled on their relative storage drums 40 and M, coil upon themselves spirally and terminate in tapered sockets 42 and 43, the socket 42 being in storage drum 4!) and the socket 43 being in storage drum 4I. The payout cable 39a before passing onto its storage drum 4I passes around a fair leader sheave 44 mounted to turn on a shaft 45. A guard 43 is provided to insure that cable 39a cannot leave the groove of sheave 44.

The coiling of the two payout cables 33 and 39a" on their respective storage drums 49 and 4| spirally affords a compact means for storage of the payout length, and at the same time increases the efiiciency of the braking apparatus the farther the payout members 39 and 39a are uncoiled. The storage drums 40 and 4| are cast as a unit preferably for mechanical simplicity and for the same reason are cast in conjunction with the brake Wheel 41. This casting which forms the members 40, 4| and 41 is preferably shown mounted on a shaft 48 and keyed thereto by means of a key 49. The shaft 48 in turn is mounted pivotally in bushings 50 which are secured preferably in the housing 34. The assembly of the shaft 48 through the casting forming drums 46 and 4| and brake wheel 41 is accomplished by means of the nonrotating bushing 5|, which when removed affords a means of entering the shaft 48 through the drum casting and also the placing of the key 49. After this the nonrotating bushing 5! is placed securely in the side of the housing 34. Of course this assembly would be accomplished with the preferred illustrated design before the housing 34 is placed in the post On the brake wheel 41 is secured a noncorrosive brake ring 52, so fastened that it must at all times revolve as a unit with the brake wheel 41 and the secured drums 46 and 4|. Enshrouding the brake ring 52 for the greater part of its circumference is the brake band 53 with the brake lining 54. At the heel or heavy end of brake band 53 a pin 55 is mounted pivotally with its outer ends pivotally mounted in side plates 56. mounted to swing on the anchor shaft 51 and this anchor shaft 51 is securely supported at each endin the sides of housing 34 as shown in the preferable construction best illustrated in Fig. 10.

Side bars 58 are secured to the inner housing 34 for the purpose of providing sufficient bearing for the ends of both anchor shaft 51 and the bushings which support rotatable shaft 48 as well as the ends of fair leader shaft 45.

At the toe end, or the light end, of the brake band 53 is secured a socket end 59 with adjustable s'et screw 60. A pivotally mounted pin 6| passes through the socket end 59 and bears against the set screw 6|] and at each end of the pin 6| an opening through the two lever plates 56 are provided so as to enable the pin 6| to transmit any movement of the lever plates 56 rotatively around the center of shaft 51 to the toe end of the brake band 53. At the same time that the pin 6| is moved about the center of shaft 51, the pin 55 moves also. Now referring particularly to Fig. 11 in case the pin 6| is moved upwardly, the pin 55 is moved downwardly and inwardly thus affording a more snug fit of the brake band 53 on the brake ring 52, and such a motion tends to bring the center line of pin 55 in a direct line between the center of the shaft 51 and the contact point of the heel end of the brake band 53 with the brake ring 52.

Any motion imparted to the lever plates 56 is through the medium. of thrust bar 62 and hand lever 63. The object of the hand lever 63 is to either set the brake 53 up tight or else release it completely from contact with the brake ring 52. The hand lever 63 when rotated about its ful crum pin 64, pivotally mounted in the support 65, to a position 63a forces the thrust bar 62 downwardly by means of the pivotal pin connection 66. This thrust bar 62 is fitted with an adjustment nut 61 and spring 68. This spring 68 These lever side plates 56 are in turn bears on a perforated pin' block 69. The two pin ears 19 of the pin block 69 are pivotally mounted in the side plates 56. The lower end of the shank of thrust bar 62 passes through the perforated center of pin block 69 as best shown in Fig. 10, and the protruding part of the shank of bar 62 is fitted with a cotter pin 1|. It is readily seen then that the movement of hand lever 63 to a position 6311 induces a tightening of the braking apparatus and vice versa, the movement of this hand lever from 63a to 63 releases the braking apparatus. The object of the spring 68 and the adjustment 61 is to provide for the possibility of having a freezing action take place between the brake band 53, its lining 54 and the brake ring 52.

This latter innovation is found to be necessary on this pertinent type of device, in that the allowable maximum diameters possible for the brake wheel within a compact housing such as one of these posts require is limited, in order to satisfy the demand of economy and compactness for commercial purposes, and on account of the extreme radial pressures exerted on the brake band surface in developing suflici'ent retardation to effectually overcome the impact load placed on the payout members 39 and 390.. This whole novel construction is made to satisfy in a compact way an extreme and difficult function; in fact special alloy steels are necessary in order to develop such a compact arrangement of parts capable of performing the difficult function requir'ed.

In order to increase the efficiency of hand lever 63 in producing a tight contact of the braking surfaces, I provide an extensible member 12 telescoping within the handle 63 and fitted with a jump-back spring 13. When the lever 63 has been forced down to the position 630. it is desirable to lock it in this latter position. For this purpose I provide locking arrangement as shown in Fig. 14 consisting of a sliding latch 14 mounted so as to slip along a shaft 15, which in turn is secured in the sides of housing 34, best shown in Fig. 12. The sliding latch 14 can be locked in place by means of the adjustable plunger 16.

From the foregoing description it can be seen that the resistive payout of the members 39 and 39a can be retarded by an abnormally heavy frictional force. But after these payout members have been run out and partially uncoiled from their respective storage drums, then it is necessary to rewind them to their normal position. Such a rewinding apparatus from a commercial point of view must be not only efiloient but must be inseparable from the post so as to be available at all times and must at the same time be housed appropriately within the shell of the post.

In my present invention I provide all of these practical and commercially acceptable features by means of the novel mechanism described below.

Mounted on and secured to the drum casting is bevel gear 11 so located as to be engageable by bevel pinion 18. Bevel pinion 1B is secured to the hand crank shaft 19 formed at its outer end so as to accommodate the hand handle 80. Shaft 19 is mounted so as to turn in swivel block 8|. This swivel block 8| has at its upper and lower ends pin ends 32 and 82a, mounted so as to be revolvable in the lugs 83 and 83a, which in turn are secured to the housing 34 as best shown in Fig. 13. It will be noted that the center of rotation of the pins 82 and 82a does not coincide with the center of rotation of bevel pinion shaft 19 at any point, the object of this being to permit a disengagement rotation of the bevel pinion 18 to a disengaged position 18a. When the pinion I8 is being rotated from its engaged to disengaged position with the bevel gear H, the judicious eccentricity of the rotation center of pins 82 and 82a from the center of shaft 19 permits the gear teeth to clear themselves as they are disengaged, and when these gear teeth are just disengaged then the shaft 19 with its attached hand handle 88 is free to rotate in the pin block 8|, the object of .this being to permit the hand handle 88 to drop down vertically, thus allowing this hand rewind device to be folded within the shell of the post I completely. A portion of the back of post i is notched out as at 84 so as to permit the hand crank 80 to be swung in horizontally suificiently to disengage the two teeth of the bevel pinion and the bevel gear.

When the payout members, cables 39 and 39a, are to be recoiled on their respective drums, the teeth of bevel gear 11 and bevel pinion 18 must remain in mesh, and to insure this I provide spring 85 fitted with key bar 86, which will engage the cross slot 81 in the top of pin 82, as best shown in Fig. 13 and Fig. 12. Spring 85 is fitted with a hand or finger hold 88 so that the key 86 can be disengaged from the slot 81 when it is desired to disconnect the recoiling hand crank apparatus.

It will be noted that not only the novelty of mechanical parts required for the commercial success of this whole mechanism have been devised, but the proper disposition of these parts and their orientation one with another on the back face of the post so as to give the operator free movement of both hands in working the brake releasing apparatus as well as the retrieving or rewinding apparatus simultaneously in a slightl stopped position while he is enabled to look directly toward the roadway barrier net or along the line of the guard rail, is no small part,

of the novelty of this invention.

A hinged cover 89 is provided on the back of the post I which can be locked in its closed position at staple 90 so as to insure that none of the apparatus within the post can be tampered with.

The cross bar 9| at the top of the frame 34 provides stiffness for this frame, yet at the same time permits access to the mechanism after the cover 31 has been removed. Anchors 92 serve as the means of anchoring the post to its foundation.

As stated in the foregoing part of the specifications I prefer to show the net of the barrier device as illustrated in Fig. 1 having diagonal members 4 similar to diagonal members 4 of Fig. 2 and diagonal members 32 of Fig. 8. By referring to Fig. 11 it is seen that the object of these diagonals is to serve as a means for pulling both the payout member 39 and the payout member 39a ofi their respective drums simultaneously, even though either one or the other of these payout members is receiving the major portion of the tensile load due to the impact of a car.

It is no doubt apparent by reference to the foregoing description and accompanying drawings, that I accomplish many advantages over the construction of similar devices that are now commercially in use, and I also provide an arrangement and construction of parts which will withstand the rough usage and extreme stresses expected of a device of this character, that the parts are housed symmetrically within rain proof and dirt proof protections where necessary, that the parts of the device necessary for successful functioning cannot be separated from the mechanism but are at all times available for use, and that these various parts can be manufactured at an economical cost.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise detail of construction set forth, but desire to avail myself of such variation and modification as come within the scope of the appended claims.

Having described my invention wh'at I claim as new and desire to secure by Letters Patent, is:

1. A device of the class described comprising a support; a flexible element arranged to pay out from said support; braking means for retarding the paying out of said element; means for rendering said braking means operative or inoperative; means for retrieving said flexible element; abevel gear for operating said retrieving means; a crank shaft foldable into and out of said support and carrying a bevel pinion normally out of engagement with said bevel gear but arranged to engage and operate said bevel gear when said crank shaft is folded out of said support; and means for utilizing the paying out of said flexible element in checking the motion of a vehicle.

2. A device of the class described comprising a support; a flexible element arrange to pay out from said support; braking means for retarding the paying out of said element; manually oper.. able means mounted within and foldable into and out of said support for rendering said braking means operative or inoperative; manually operable means mounted within and foldable into and out of said support for retrieving said flexible element; and means for utilizing the paying out of said flexible element in checking the motion of a vehicle.

3. The device specified 'in claim 2 in which both the braking and retrieving means are provided with means for selectively locking them in either their operative or inoperative positions.

EMERSON D. SAWYER,

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